Adsorbent granulate and method for the manufacture thereof

ABSTRACT

The invention relates to a X-zeolite based adsorbent granulate with faujasite structure and a molar SiO 2 /Al 2 O 3  ratio of ≧2.1-2.5, wherein the granulate has an average transport pore diameter of &gt;300 nm and a negligible fraction of meso-pores and wherein the mechanical properties of the granulate are at least the same as or better than the properties of an X-zeolite based granulate formed using an inert binder and the equilibrium adsorption capacities for water, CO 2  and nitrogen are identical to those of pure X-zeolite powder with a similar composition.

The invention relates to an adsorbent granulate based on zeolite with afaujasite structure and to a method for the manufacture thereof. Theinvention furthermore relates to using the granulate as an adsorptionagent preferably for a selective separation, purification and drying ofgases and liquids.

Adsorption agents based on zeolites with their specific properties likehigh chemical and thermal resistance, the existence of a homogenouschannel pore system in the sub nanometer range and the development ofspecific interactions with adsorbed molecules based on a variable kationcomposition have an outstanding economic significance [“The Economics ofZeolites, Sixth Edition”: Roskill Inf. Serv. Ltd, London, UK, 2003].

Besides rather classical applications in the fields of drying gases orliquids (static applications in insulating glass window,dynamic-regenerative applications in the field of crude oil and naturalgas processing) this relates in particular to an application in thefield of air fractionizing (cryogenic or non cryogenic), whereinadsorption agents based on faujasite-zeolite (type X) are being used ona large scale. [A. Pfenninger: Proc. Ind. Appl. Zeol., Brugge, 2000,73.]. The term faujasite-zeolite defines a class of crystallinealumosilicates which were originally discovered as a natural mineral,however, only the synthetic products with said faujasite structures havegained economic relevance. Within these zeolites with faujasitestructure another classification according to their composition(especially according to the molar ratio SiO₂/Al₂O₃) has become popular.Thus products with a ratio SiO₂/Al₂O₃>3.0 are designated as Y-zeolitesand those with a SiO₂/Al₂O₃<3.0 as designated X-zeolites.

Another classification of the X-zeolites according to their SiO₂/Al₂O₃ratio was historically derived from the development of differentsynthesis variants. Thus for a long time a “feasibility limit” for theX-zeolites was perceived at a SiO₂/Al₂O₃ ratio of approximately 2.46[cf. e.g. U.S. Pat. No. 4,289,740]. These products are designated as13X-zeolites. Later, however, also synthesis variants for X-zeoliteswith SiO₂/Al₂O₃<2.6 were developed. Thus, another differentiation ismade between the so called LSX (low silicon-X) with a SiO₂/Al₂O₃ of2.0+/−0.1 and MSX (medium silicon X)-zeolites (subsequently referred toin this patent application) with a SiO₂/Al₂O₃ ratio in the range >2.2 toapproximately 2.45. The differentiations recited supra are useful sincedifferent synthesis methods are also being used for the different subtypes. Thus, Y-type faujasite-zeolites are typically produced using a“pure” SiO₂/Al₂O₃ base component controlled, back feed of the basecomponent from the “mother base” and possibly using a germinationsolution [e.g.: Costenoble u.a.: J/Chem. Soc., Faraday Trans. I, 72(1976), 1877], while the synthesis of LSX type faujasites-zeolites isgenerally performed in the presence of caustic potash solution besidesthe otherwise typical caustic soda solution [e.g. DE 2.731.010] orthrough the application of high pressures [U.S. Pat. No. 4,289,740]. Thesynthesis variants also differ significantly for a 13× with a SiO₂/Al₂O₃ratio of approximately 2.5 from the synthesis variants for theproduction of the MSX.

Among the X types the “classic” 13X-type has the most significance basedon volume. This relates to its use as an adsorption agent whenprocessing raw air cryogenic air fractionizing devices for processingnatural gas or also for non cryogenic oxygen enrichment through pressurechange adsorption technology. However, there is an increasing trend touse the more powerful MSX-types for this application. LSX-types arebeing used (preferably as materials including Li) for the non cryogenicoxygen enrichment through pressure change adsorption technologydescribed supra [M.-T. Grandmougin, R. Le Bec, D. Plee: Ind. Appl:Zeol., Brugge, 2000, 93].

The present invention relates to the preceding paragraph and relatespreferably to granulates for molecule sieves based on X-zeolites, inparticular X-zeolites with a molar SiO₂/Al₂O₃>2.1-2.5.

As a matter of principle one would like to use the adsorption properties(selectivity and capacity) of the respective “pure” zeolite componentfor all molecular sieves based on zeolites. While one could use zeolitemolecular sieves in principle in the form of powder (primary form aftersynthesis) for static adsorption processes this, however, is notpossible for dynamic processes (in a flowing medium) or only possiblewithin limits, since excessive pressure drops over a powder pile renderthe method inoperative. Thus, in these cases one has to use formelements of any shape [A. Pfenniger in “Molecular Sieves—Science andTechnology”, Volume 2, Springer-Verlag, 1999, 163]. This touches on thebasic problem for the conceptional configuration of adsorption agentsfor dynamic processes: On the one hand shaped bodies are required inorder to be able to actually operate the processes in a dynamic manner.For known reasons these shaped bodies have to comply with particularminimum requirements with respect to their mechanical properties (dust,abrasion, pressure resistance, pouring weight). On the other hand shapedbodies are disadvantageous, since on the one hand side the activecomponent is only provided in a thinned form in those formed bodieswhich include binder material and on the other hand the actually desiredadsorption and desorption at the zeolite active component can besuperimposed by the material transport processes in the formed bodies.Typically, the more mechanically stable the shaped body, the lessdisadvantageous are the material transport processes.

In the art shaped bodies in spherical form are being used, which aretypically produced through layered granulation using a natural claybinder or extruded shaped bodies (cylinders, hollow cylinders, woundstrands), typically using clay or other silicate binder materials [e.g.:W. Pietsch: Aggl. Proc.: Phen., Techn., Equipmt.: Wiley-VCH, Weinheim,2002].

All recited shaped bodies have in common that as a function of the sizeof the shaped bodies, which in turn is determined by the applicationprocess and/or the volume of the binder material used, more or lessstrong influences of the material transport processes recited supra haveto be considered. For example, typical granulates deformed with clayminerals and including zeolite always show a comparatively highpercentage of pores in the portion of the transport pores (measuredthrough mercury high pressure porosimetry) wherein the pores have adiameter <50 nm, (so called meso-pores), which are known to restrict themovability of the molecules when transported to and from the adsorptioncenters in the zeolites.

A transport pore system is desirable for technical adsorption agents,wherein the system only includes a negligible percentage of meso-poresand a mean pore diameter which is as large as possible [D. Bathen, M.Breitbach: “Adsorptionstechnik”, Springer-Verlag 2001, 13.]. The problemof the restricted movability of the molecules in the granulate ofzeolite-containing molecular sieves deformed by clay binders can bealleviated by keeping the shaped bodies relatively small with respect totheir dimensions (short transport paths), wherein in this case, however,the occurring pressure drop in an adsorption material compilationrestricts the use of these small particles to low pouring heights orsmall devices. Large, but highly porous formed bodies can be usedalternatively. It is an option to produce larger granulates bound withclay minerals with an improved transport pore system by adding atemporary pore forming agent to the granulate during deformation,wherein the pore forming agent can be typically broken down thermallyand which is burned out after the deformation is formed and after asubsequent thermal treatment and wherein the pore forming agent leavesbehind a respective pore forming system. [JP 62283812]

Unfortunately, the classic zeolite types (A and in particularfaujasites), however, are more sensitive with respect to thermal(hydrothermal) treatment. Thus, the thermal breakdown of the poreforming agents has to be performed, so that said thermal/hydrothermalloading of the granulate is avoided which causes additional complexity.The problem of thermal loading furthermore already relates to thebinding of the typically used mineral binding agents (like e.g.Attapulgit) which have to go through a thermal treatment in the range of500->600° C. [cf. e.g. U.S. Pat. No. 6,743,745].

In the art, however, in any case the problem of “thinning” the actualactive component through an inert binder material, though it may be veryporous, remains in any case for zeolite containing granulates which arebound by inert clay materials.

Methods are known in which it is being attempted to maximize the portionof active components in zeolite containing shaped bodies. Among them arein particular the methods for producing so called zeolite containingshaped bodies without binder material. When producing these productsessentially two paths are being taken. On the one hand side a rawmaterial which is suitable with respect to its deformability andchemical composition (mostly kaoline) is formed into a shaped body andthe shaped body is subsequently converted into a material completelymade from zeolite through thermal and/or chemical post treatment [e.g.U.S. Pat. No. 3,119,660]. This was already described decades agopreferably for zeolite type A. This is the case in particular becausekaoline in its composition with reference to SiO₂/Al₂O₃ content comesvery close to the composition of zeolite A. A direct conversion offormed kaoline over meta-kaoline into zeolite material of the faujasite(X-type) is not known, however, the conversion of a meta-kaoline formedbody including sodium silicate and a pore forming agent into zeolitematerial of the faujasite type is known. The quality of the materialthus obtained is only described by the content of zeolite type-Xmaterial of 73%-74%, determined by the x-ray method. U.S. Pat. No.4,818,508 discloses a similar method; however the use of a mandatorypore forming agent is described herein in order to be able to assure themost complete transformation into zeolite material possible. Anotheroption to produce binder-free zeolite containing formed bodies iscomprised in deforming a powder of a certain zeolite-type with asuitable binder material, possibly a mix of several products, andsubsequently converting the binder portion into zeolite. For thedescribed method kaoline or meta-kaoline (a thermally activated kaoline)play an important role again [U.S. Pat. No. 3,119,659]. Also in thiscase kaoline/meta-kaoline used as binding agent is converted intozeolite material through subsequent thermal-chemical treatment.

Over a long period of time the binder-free zeolite including molecularsieves of Bayer AG were commercially available and known under the tradename “BAYLITH”. These manufacturing methods are described in severalpatent documents (e.g. DE 1.203.238). In principle silica gel is used asa primary binding agent, wherein the silica gel is introduced into thesystem in different partially very complex ways. Mixtures of silica soland magnesium oxide suspension or sodium silicate are described thereinas gel forming systems. The silicate binder portion formed in thismanner is then in turn converted into zeolite material in a subsequentstep. It is typical for the method recited supra, wherein the bindingagent portion is converted, that the binding agent, irrespective of thetype of the zeolite component introduced, is intentionally convertedinto zeolite type A, thus also the product with the designation BAYLITHW894, wherein a type X material (faujasite) is introduced into thedeformation as a zeolite. The result of the entire process is a shapedbody which includes zeolite X and zeolite A [GB 1,348,993]. Anotherdisadvantage of the method recited supra appears to be the porosity ofthe SiO₂ containing shaped bodies which is detrimental for furtherprocessing. Thus it is specifically indicated e.g. in [DE 2,016,838]that in particular for larger granulate diameters a relatively longworking period is required for the solution for converting the SiO₂portion into zeolite material before the actual conversion and arelatively long watering of the converting granulate is required inorder to achieve on the one hand the most complete conversion of theSiO₂ content into zeolite material possible and on the other side toachieve the desired very open transport pore system. Typically in theseproducts a significant percentage of transport pores with a diameter ofless than 50 nm (meso-pores) is detectable, though this is much lessthan in granulates deformed with mineral clay based binder materials.

In the course of introducing the LSX-zeolites recited supra as powerfuladsorption agents for non cryogenic oxygen enrichment through pressurechange adsorption technology, there have been increased efforts sinceapproximately the mid 1990's to also produce LSX-type molecular sieveswhich are free from binding agents. Thus, the method principles recitedsupra are transferred analogously. Thus, products produced according tothe “BAYER” principle include type LSX and type A [U.S. Pat. No.5,962,358].

For products which were produced on a kaoline/meta-kaoline base theillustrated results are quite contradictory. However, two detrimentaltrends are apparent. Either well crystallizing products, however, withan insufficient mechanical stability are obtained through the conversionof the kaoline/meta-kaoline into zeolite material, or mechanicallystable products are obtained which besides the desired LSX structurealso include other crystalline structures as “extraneous phase” (e.g.zeolite-A or zeolite-P), or in which the conversion into the desiredstructure is not performed up to the theoretically possible extent [cf.U.S. Pat. No. 6,478,854 and citations included therein].

In conclusion it is appreciated that up to now there is apparently noefficient method for producing mechanically stable binder material freemolecular sieve granulates based on X-zeolite, wherein the molecularsieve granulates are exclusively made from zeolite-X material. Thisrelates at least to products with a SiO₂/Al₂O₃ ratio in a range>2.1-2.5.

Based on the described art it is the object of the invention to providea low cost mechanically stable granulate based on a zeolite withfaujasite structure and with a SiO₂/Al₂O₃ ratio in a range of >2.1-2.5,wherein the granulate includes an optimum transport system with anegligibly small portion of meso-pores and the highest possible meandiameter of the transport pores and a maximum content of zeolitematerial with a faujasite structure and an SiO₂/Al₂O₃ ratio in a rangeof >2.1-2.5. The granulate shall be usable as a highly efficientadsorption agent for technical adsorption processes.

The object is achieved by intensively mixing a powdery zeolite of theX-type with a molar SiO₂/Al₂O₃ ratio of >2.1-2.5 initially with apowdery thermally treated kaoline into this mix a solution includingsodium hydroxide and sodium silicate is added and mixed intensively aswell as the mixture thus produced is converted in a known manner withthe addition of water into an evenly configured granulate. The granulateis dried and hydrated after the drying and treated with a solution ofsodium hydroxide and sodium aluminate subsequently separated from thissolution, washed, dried and tempered.

Surprisingly it was found that the shaped bodies thus produced have thedesirable properties described supra to be achieved as objects of theinvention and the disadvantages of existing/described products known inthe art were eliminated. Particularly advantageous is the fact that theshaped bodies at least for water, carbon dioxide and nitrogen undercomparable measurement conditions have the same weight adsorptioncapacities as the zeolite powder used as a base product (in activatedcondition). It is furthermore advantageous that the granulate does nothave to be exposed to temperatures above 400° C. during its entireproduction process. This yields energy and thus cost savings and thezeolite structure is simultaneously treated gently.

The method described supra will be described in more detail now.

Dried X-type zeolite powder is used as base material now with a molarSiO₂/Al₂O₃ of >2.1-2.5, preferably with a molar SiO₂/Al₂O₃ ratio of2.25-2.45. For this purpose said X-type zeolite is also usable whenconfigured as a filter cake or slurry, wherein the respective moisturecontent has to be considered accordingly when computing the granulationmix.

The thermally treated kaoline used as another base component isgenerated from commercially available raw kaoline. It is essential toselect this raw kaoline based on the content of non-kaoliniticcomponents (in particular silica and feldspar). The content of theseextraneous components which cannot be converted into zeolite materialthrough further processing should be <mass-% preferably <1 mass-%.

The thermal treatment of this raw kaoline is preformed e.g. in atemperature range of 600° C. to 800° C., preferably in a range of 620°C. to 800° C. For a thermal loading the firing loss of the raw kaoline(one hour, 950° C.) is reduced from 14% to approximately 1%.

When necessary, the thermally treated kaoline has to be run through amilling process before further processing, since it has provenadvantageous to use material with a mean particle size of <10 μm. Thethermally treated kaoline is mixed with the zeolite component at a massratio of 1:1 to 1:5, preferably at a mass ratio of 1:2 to 1:3.5respectively with reference to the absolutely water free material of thetwo components. A solution including sodium hydroxide and sodiumsilicate is added to the mix and intensively mixed.

The mixing can be performed in known devices, like e.g. drum mixers,cyclone mixers, plow share mixers. In any case intense mixing of thecomponents has to be assured.

The mixture recited supra is transferred into an evenly formed granulate(preferably ball granulate) through known techniques. For example mixinggranulators, plate granulators or cyclone granulators can be used forequipment. When necessary water is added to the mixer during thegranulating process.

The finished granulate is dried at temperatures of 10° C. to 100° C.,preferably 40° C. to 70° C. The drying can be performed in a staticambient or inert gas atmosphere, however, it has proven advantageousthat the granulate to be dried is flowed through by ambient air.

The dried granulate is subsequently hydrated with completely desalinatedwater in order to remove adhering dust particles and also to improve theaccessibility of the transport pores for the zeolitization step. Thisprocess can be performed in a suitable stirring vessel or also in acolumn continuously flowed through with flushing water and filled withgranulate. The ratio of water to granulate is preferably in a range of5:1 to 40:1, preferably in the range of 8:1 to 20:1. The temperature ofthe water used for flushing should be in a range of 15° C. to 40° C.,preferably the watering is performed at ambient temperature. Thetreatment time is 5 minutes to 120 minutes, preferably 15 minutes to 60minutes.

The watered granulate is subsequently treated with a solution includingthinned sodium hydroxide solution with an addition of sodium aluminatesolution. The treatment can be performed in a suitable stirring vesselor also in a column that is continuously flowed through by the solutionand filled with the granulate. The ratio of solution to granulate istypically in a range of 5:1 to 40:1, preferably in a range of 8:1 to20:1. The treatment temperature for this process step is in a range ofe.g. 70° C. to 95° C., preferably in a range of 75° C. to 90° C. Theduration of the treatment is in a range of 8 to 24 hours and isdetermined in detail by the achieved degree of conversion of thepreviously non zeolite granulate portions into the desired zeolitematerial.

An “aging step” can be performed before this treatment using an alkalinesolution with a similar composition or of the same solution, however ata lower temperature, preferably at ambient temperature over a timeperiod of 0.5 to 24 hours, preferably 1 to 4 hours. After the treatmentis completed the granulate is separated from the treatment solution andis washed with completely desalinated water in the same basic manner asdescribed supra until a ph-value <12 is reached in the washing water.

The used treatment solution from the conversion can be reconditioned andcan be used for a subsequent treatment step with new granulate.

The washed granulate is separated from the washing water, dried andtempered. The recited thermal steps have to be performed under suchconditions that a thermal/hydrothermal damaging of the material isexcluded. Preferably devices are being used in which the granulate iscontinuously flowed through by dry air or inert gas and where thetemperature can be increased incrementally. The duration of thesethermal steps and the end temperature have to be selected, so that thematerial includes the required minimal humidity content (typically <1%mass). Thus, in the present situation maximum temperatures <450° C. aresufficient.

The subsequent embodiments and descriptions are intended to illustratethe basic principle of the invention.

EMBODIMENT 1 NaMSX-Base Component

NaMSX powder manufactured through industrial production methods withsubsequent properties was used as a base material:

SiO₂/Al₂O₃: approx. 2.35

d₅₀: approx. 3.5 μm

LOI (1 h, 950° C.): 21.4% mass

EMBODIMENT 2 Reference Embodiment

The material described in this embodiment is a molecular sieve producedin a conventional manner through industrial production techniques basedon a NaMSX zeolite powder with a SiO₂/Al₂O₃ ratio of approx. 2.35 (re.embodiment 1) in a typical kernel size range of 1.6-2.5 mm. AnAttapulgit (type Clarsol (Zeoclay) ATC NA, CECA) at a ratio of 17% masswith reference to the material in activated state was used as a bindermaterial. The activation was performed in a conveyor belt oven withdifferent temperature zones and a final temperature of 540° C.

EMBODIMENT 3 According to the Invention

In order to produce the base granulate, 733 g of zeolite NaMSX with amolar SiO₂/Al₂O₃ ratio of 2.35 and a firing loss of 21.4% (cf.embodiment 1) are mixed in a MTI-mixer with 223 g of a kaoline of the KSbrand (vendor DVS Co. Limited/Ukraine composition cf. Table 1)pretreated at 700° C. for 1 hour in a muffle furnace with a firing lossof 1% dry material.

In a separate container 257 g of a 5% sodium hydroxide solution is mixedwith 257 g of sodium silicate with a SiO₂ content of 27.5% and Na₂Ocontent of 8.3% through intense stirring.

In order to perform the granulation, 500 g of dry mix made form zeoliteand meta-kaoline are put into the MTI-mixer and small amounts of theprepared solution of sodium silicate and sodium hydroxide are addeduntil substantial granulation occurs in the super humid mixture disposedin the mixer. As soon as the granulate has reached the desired kernelsize of approx. 1.5-3 mm, the mixture is powdered by adding smalleramounts of the dry mix including zeolite and calcinated kaoline. Theobtained raw granulate is subsequently rounded out on a Rotorcoator. Themoisture thus extracted is compensated by adding smaller amount of drymix in order to prevent the particular granulate kernels from gluingtogether.

The obtained granulate is dried in a ventilated drying chest for 20hours at 60° C. (layer thickness, approx. 2 cm) and subsequently sievedinto 2 fractions.

In order to perform the zeolitization, 30 g of the 1.6-2.5 mm fractionof the granulate are hydrated 3 times with 200 ml of de-ionized water inorder to remove all adhering dust particles. Subsequently the granulateis left for another 30 minutes under 300 ml of de-ionized water. Thewater is mostly poured out after this time period and replaced with thereaction mix for the zeolitization. The zeolitization is performed byadding 1.75 g of technical sodium aluminate hydroxide with a content of19.5% each of Na₂O and Al₂O₃ in order to produce 320 g of 3% sodiumhydroxide. As described supra, this solution is added to hydrated humidbase granulate and the mix made from granulate and reactive solution isaged for a period of 4 hr. at ambient temperature. During this timeperiod the vessel is shaken lightly from time to time in order to limitin homogeneities in the composition of aging solution to a minimum.

After the completion of the aging process the reaction vessel is placedin a water bath and heated to a temperature of 83° C. Thus, the vesselis closed, so that evaporation of the liquid is essentially excluded.Subsequently the zeolitization reaction is performed at this temperatureover a time period of 16 hr.

After the reaction time has expired the reaction vessel is removed fromthe water bath and the superfluous mother hydroxide is poured out aftercooling down to 50° C. and discarded. Subsequently washing with approx.200 ml deionized water is performed and the washing water isrespectively removed by decanting. Subsequently the granulate is leftunder 300 ml of water for 5-10 min., thereafter sucked out with aBUECHNER funnel and washed again two times with 200 ml of de-ionizedwater each, evacuated hard and subsequently dried under an infrared lampat approx. 60° C. for approx. 30 minutes.

In order to determined the x-ray crystallinity and the extraneous phasecontent 0.8 grams of the dried granulate are milled over for 10 minutesin a ball mill. The obtained powder is then placed on a sample carrierand checked for the crystallinity of the obtained zeolite type-X phaseand for the non presence of crystalline extraneous phases using adefractometer type “D4 ENDEAVOR” made by Bruker-AXS GmbH, Karlsruheusing the software package “DIFFRACplus”. For the granulate producedaccording to this embodiment this yields and x-ray crystallinity of 90%and a lack of crystalline extraneous phases.

In order to determine the chemical composition, 1.2 g of the drygranulate is milled for a time period of approximately 20 min. in a ballmill and subsequently pressed to form a pressed spar-component accordingto SCHRAMM using 6 g of crystalline boric acid. The composition of thissample is then determined at an x-ray spectrometer of the type “S4explorer” made by Fa. Bruker-AXS GmbH, Karlsruhe using the “SPEC plus”software package. Thus, the molar ratio of SiO₂/Al₂O₃ and Na₂O/Al₂O₃ isdetermined using a respective calibration while the content of otherelements is obtained as a measurement without standard using the linelibrary of the software package. The SiO₂/Al₂O₃ ratio thus determined(“module”) is 2.34 and thus corresponds almost exactly to the module ofthe NaMSX powder used for producing the base granulate. Besides the maincomponents SiO₂, Al₂O₃ and Na₂O, additionally the granulate includes0.2% TiO₂, 0.2% Fe₂O₃ and respectively close to 0.1% CaO and K₂O.

The pressure resistance determined at the dried granulate wasapproximately 31 N/ball.

In order to determine the equilibrium adsorption capacity for water 2 gof the dry granulate are activated at 450° C. for a period of approx. 1hr. and the activated sample is subsequently cooled in an exsiccatorover phosphorous pent oxide. Subsequently, the sample is placed into aweighing glass in an exsiccator with thinned sulfuric acid, whose vaporpressure at 25° C. corresponds to the partial pressure of water at 55%relative humidity. The exsiccator is evacuated until the sulfuric acidbegins to boil and left in this condition for 24 hours. The adsorptioncapacity for water is then computed from the mass increase. Since nochange in the sample mass was detected after another 24 hr. of dwellingtime in the exsiccator, it was safe to presume that the adsorptioncapacity corresponds to the equilibrium adsorption capacity of theanalyzed granulate sample for water vapor (result cf. Table 2).

In order to determine the adsorption capacity for nitrogen and carbondioxide 0.4 g of the dry granulate is activated in a test tube in asample preparation station type “VacPrep 061” made by the MicrometricsCompany (USA) under vacuum for a period of 3 hrs. at 400° C. andsubsequently measured at 25.0° C. in an adsorption measurement devicetype “Gemini 2370” made by the Micrometrics Company (USA) with therespective measurement gas as an adsorptive. The obtained adsorptionvalues are included in Table 2 and within the measurement precisioncorrespond to the values determined for the NaMSX powder used forproducing the base granulate.

EMBODIMENT 4 According to the Invention

A meta kaoline powder is used for producing larger amounts of the basegranulate for zeolitization, wherein the meta kaoline powder is obtainedby calcinating the kaoline with the brand “Super Standard Porcelain”made by the IMERYS Co. in a rotating tube kiln at a maximum producttemperature of approx. 720° C. and a dwelling time of approx. 1 hr. withsubsequently milling in a jet mill to a defined mean particle size. Thusthe composition of the base kaoline is included in Table 1. Though thematerial is almost silica free, it apparently includes significantamounts of potassium feldspar. This can be derived from the relativelyhigh K₂O content and also from the presence of the respective reflexesin the x-ray diffractogram.

For producing base granulate respectively 24.1 kg NaMSX powder with afiring loss of 21.4% and a module of 2.35 (cf. Embodiment 1) are mixedwith 7.4 kg of the meta-kaoline powder described supra in an EIRICHmixer of the R7 Type in a dry state. This dry mix is then slowlycomplemented with respectively 8.5 kg of a solution of 7.7 kg of sodiumsilicate (with a SiO₂ content of 27.5% and a Na₂O content of 8.3%) and0.8 kg of a 48% sodium hydroxide. This premix is then mixed until asubstantial degree of homogeneity is achieved. This process is repeatedseveral times in order to obtain sufficient amounts of granulatablepremix.

In order to begin the granulation the last of the produced 40 kg batchesof the premix is left in the EIRICH mixer and the granulate formation isinitiated by slowly adding water. After the granulate formation begins,a dusting with the premix and a humidification with water is performedin an alternating manner until the desired granulate spectrum of approx.1.5-3.0 mm is reached. The completely granulated mixture is thenseparated in a sifting device into a usable kernel fraction, a undersize kernel fraction and an oversize kernel fraction. The oversizekernel fraction is then subsequently crushed in an EIRICH mixer and fedback into the granulation process together with the under size kernelfraction as reclaimed material. The subsequent granulation process isthen performed respectively using premix and reclaimed material.

The usable kernel fraction of the obtained fresh granulate is then driedin a chamber dryer with air circulation in a layer thickness of approx.2 over the course of 24-36 hours and used as a base granulate for thesubsequent zeolitization.

In order to perform the zeolitization 8.5 kg of dry granulate are placedinto a flow through reactor with a remove able insert with approximately15 cm interior diameter and approx. 70 cm useable height and watered for30 min. with de-ionized water in a flow cycle. In parallel thereto areactive solution is prepared in a separate storage container, whereinthe solution includes 200 liters 3% sodium hydroxide and 1.1 kg of atechnical sodium aluminate hydroxide with a content of 19.5% Na₂O andAl₂O₃ respectively. This reactive solution is then pumped over thepre-washed granulate with a temperature of 23° C. and a flow throughvelocity of 200 l/h for 2 hours. After this aging period the reactivesolution is heated to 83° C. with vapor through a bypass heat exchangerand the zeolitization is performed over a period of 16 hours. After thistime period has expired the mother base is drained and the granulate iswashed with three portions of 200 liters of de-ionized water each.

The humid granulate is then removed from the reactor together with theinsert and dried for approx. 8 hrs. in an air flow at a maximumtemperature of 50° C. After the drying an incremental activation up to380° C. is performed. The granulate obtained has a residual watercontent of <1.0%. The modulus of the granulate determined through x-rayflorescent analysis is 2.37 and thus approx. corresponds to the valuefor the NaMSX powder which was used to produce the base granulate.

For the granulate produced according to this embodiment an x-raycrystallinity of 86% and a lack of crystalline extraneous phases isdetected.

The data regarding the adsorption properties and the pressure resistanceand regarding the granulate obtained are included in Table 2. Theobtained adsorption properties correspond approximately to theadsorption properties of the NaMSX powder used for producing the basegranulate. The slightly lower adsorption capacity for carbon dioxidecompared to embodiment 1 can be explained by the detectable content ofthe potassium feldspar in the meta-kaoline used. Apparently, thispotassium feldspar is not converted into the zeolite phase or notsufficiently converted.

TABLE 1 Composition for the kaolines in delivered form as used forproducing the base granulates Content (in % m/m) of: Kaoline SiO₂ Al₂O₃Na₂O K₂O TiO₂ Fe₂O₃ H₂O KS 45.1 38.1 0.1 0.3 0.7 0.7 14.5 Super 47.836.0 0.2 1.4 0.02 0.5 13.4 Standard Porcelain

TABLE 2 Important parameters for the granulates included in theembodiments 1-4 compared with the 13-X powder used for producing thebase granulates CO₂-Adsorption N2 Adsorption Crystallinity WAC (Ncm³/g)(Ncm³/g) Pressure Embodi- (XRD) (static) at 25° C. and at 25° C./Resistance ment % i/i Module % m/m 1.8 T 34 T −250 T 750 Torr N/Ball 198 2.35 30.8 34.5 80.0 118.0 10.2 — 2 81 (2.35) 27.6 26.0 63.5 95.5 8.235 3 90 2.34 30.3 34.9 80.4 118.4 10.2 31 4 90 2.37 30.9 34.2 78.5 116.310.1 37 Comment: WAC—water adsorption capacity at 25 C. ° and 55%relative humidity

Based on the results according to Table 2 it can be determined that theproducts according to the invention with respect to their mechanicalstability are at least comparable to conventional products. Thecrystallinities of the portion of zeolite material in the granulatedetermined through x-ray diffractometry for the products according tothe invention are higher than comparable conventional products.Surprisingly, adsorption capacities can be found at the productsaccording to the invention which are substantially identical to theadsorption capacities measured for pure powder. This indicates that theproducts according to the invention are actually made from almost 100%zeolite material of the desired structure. The apparent contradictionbetween zeolite material contents in the granulate determined on the onehand side through x-ray diffractometry and one the other hand sidethrough adsorption measurements can be explained in that a portion ofthe zeolite material detected through adsorption is not detectablethrough x-ray diffractometry, thus it is “x-ray amorphous”. Thissituation occurs when the respective crystallites are too small to causex-ray diffraction. Thus, it can be presumed that during the“zeolitization” with reference to embodiments 3 and 4 approx. 10% of thezeolite material has been created with particle sizes below thedetection threshold of x-ray diffractometry, thus nano particles whichaccording to all current experiences should have advantageous propertiesin adsorption applications.

FIGS. 1 through 5 illustrate pore radius distributions of the productsaccording to embodiments 2-4 measured through mercury porosimetry. Themeasurements were performed with the equipment combination PASCAL P140,P440 made by the Porotec Co. Initially interfering gases were removedfrom the sample surface in a vacuum. Thereafter an incremental pressureincrease up to 400 kPa was performed in the low pressure porosimeterP140. Thereafter the sample is put into the high pressure station atambient pressure and the pressure is increased up to 400 mPa. Through aparticular method (PASCAL) the pressure change gradients are varied as afunction of the pressure range and as a function of the mercuryadsorption by the probe. The mercury volume penetrating the probe isregistered and a pore size distribution is determined. Based on acomparison of FIGS. 2-5 with FIG. 1 it can be determined that theproducts according to the invention only include a negligibly smallpercentage of undesirable transport pores with a diameter <50 nm(Mesopores). The properties are already formed during the production ofthe base granulate (fresh granulate cf. FIG. 3): The subsequent processsteps (watering, zeolitization, washing, drying and tempering, cf. FIGS.4 and 5) lead to movement of the transport pore spectrum to largerdiameters and/or to an elimination of still existing meso-pores throughe.g. crystallization processes. In particular the products according tothe invention have significant advantages in their application indynamic adsorption processes based on the transport pore system overconventional products, in particular for adsorption processes with aquick change between adsorption and desorption.

1. An adsorption agent granulate based on zeolites, comprising: afaujasite structure, a molar SiO₂/Al₂O₃ ratio of ≧2.1-2.5, a meantransport pore diameter of >300 nm, wherein the transport pores includemeso pores and macro pores and the meso-pore fraction is <10%,preferably <5% with mechanical properties which facilitate safe handlingof the granulate an sufficient processability.
 2. The adsorption agentgranulate according to claim 1, wherein the pressure resistance measuredat a dried granulate with a diameter in a range of 1.6-2.5 mm is ≧30N/ball.
 3. The adsorption agent granulate according to claim 1, whereinthe static adsorption capacity in at least 96% of the value for azeolite powder with the same structure and composition and thecrystallinity of the zeolite portion determined through x-ray graphicsis >85%.
 4. A method for producing an adsorption agent granulateaccording to claim 1, wherein a X-type zeolite with a molar SiO₂/Al₂O₃ratio ≧2.1-2.5 provided as a dry powder, filter cake or slurry is mixedat a weight ratio of 1:1 to 1:5 with a thermally treated kaoline with amean particle diameter in a range of ≦10 μm which may include ≦5 mass %non kaolinitic material, the mixture is then mixed with a mixture ofsodium hydroxide and sodium silicate solution, the mixture is formedinto a granulate the granulate is subjected to a drying process andsubsequently hydrated with completely de-salinated water and treatedwith a sodium aluminate solution at temperatures in a range of 70°C.-90° C. over a time period of up to 24 hours, then the granulate thustreated is separated from the solution, washed, dried and tempered.
 5. Amethod according to claim 4, wherein the temperature for thermallytreating the kaoline is in a range of 600° C. to 850° C.
 6. A methodaccording to claim 4, wherein the ratio of washing water to granulate isin a range of 5:1 to 40:1, preferably in a range of 8:1 to 20:1.
 7. Amethod according to claim 4, wherein the hydrated granulate is treatedwith a solution including thinned sodium hydroxide solution with anaddition of sodium aluminate solution.
 8. A method according to claim 7,wherein the ratio of solution to granulate is in a range of 5:1 to 40:1,preferably in a range of 8:1 to 20:1.
 9. A method according to claim 4,wherein the duration of the treatment with the sodium aluminate solutionis determined by the obtained degree of conversion of non zeoliticgranulate components into desired zeolite material.
 10. A methodaccording to claim 4, wherein an aging step with sodium aluminatesolution or a solution with the same ingredients but anothercomposition, however, at a lower temperature is performed over a timeperiod of 0.5-24 hours, preferably 1-4 hours before performing thetreatment with the sodium aluminate solution.
 11. An adsorption agentconsisting of or comprising an adsorption agent granulate producedaccording to claim
 4. 12. A method for using the adsorption agentaccording to claim 11 in processes for oxygen enrichment, hydrogenpurification, natural gas processing, energy storage and similaradsorption processes.